1. Field of the Invention
The present invention relates to an organic light emitting display (OLED) and method of fabricating the same, and, more particularly, to an OLED and method of fabricating the same, which can substantially prevent a short circuit between a pixel electrode and an opposite electrode.
2. Description of the Related Technology
An organic light emitting display (OLED) is quite appropriate for use to display moving images irrespective of its size because the OLED has a fast response speed of 1 ms or less, consumes low power, and is an emissive display element and therefore has a wide viewing angle. Also, the OLED can be fabricated at low temperature and in a simple process based on conventional semiconductor manufacturing technology. For these reasons, the OLED has attracted much attention as the next-generation flat panel display (FPD) element.
FIG. 1 is a cross-sectional view of a unit pixel of a conventional OLED.
Referring to FIG. 1, a pixel electrode 150 of the OLED is connected to a drain electrode 130b of a thin film transistor “E” through a via hole 145 formed in a planarization layer 140. An organic layer 160 including an emission layer and a pixel defining layer 155 are disposed on the pixel electrode 150, and an opposite electrode 165 is disposed on the resultant structure.
In the above-described structure, it can be seen that the pixel defining layer 155 formed in a portion “A” of the via hole 145 is thin in the vicinity of an etched portion t1 of the planarization layer 140.
FIG. 2 is a photograph of the portion “A” of the via hole 145 of FIG. 1.
Referring to FIG. 2, the thickness t1 of the pixel defining layer 155 in an end portion “B” of the planarization layer 140 is formed thinner than the thickness t2 of the pixel defining layer 155 formed in the via hole 145. As a result, when the opposite electrode 165 is formed on the pixel defining layer 155, a short circuit between the opposite electrode 165 and the pixel electrode 150 may arise. The short circuit may lead to a failure in a unit pixel, causing dark spots when the OLED is driven.